Thanks Wolfgang ...Thats the problem with the ASM frame window size , the cylinders were longer in the early years ...
This one is 1978 and it has the longer cylinder I measured yesterday ...2.018
My newer ASM had a 2.0 and it was a 1999 made
anyway I did some searching on the net and found this which helped .
Pietta cylinder ..2.018
So it looks like Pietta cylinders will fit the older ASM Remmies and Uberti will fit the newer .
I also noticed there are no stampings on the side of this older ASM all the proof marks are on the underside of the gun ..
and the newer one had stampings on the top and sides of the barrel and frame .
This 1978 one I just bought came to me still unfired new in the box ....fit and finish is as nice as Uberti on this one , shes a keeper ...